The invention relates to a brush unit for electric machines. A preferred field of application of the brush unit is in electric motors for motor vehicles, in particular starter motors (starters) for internal combustion engines.
Higher requirements are increasingly being placed on starter motors (starters) in automobiles with respect to the service life and performance, these being created partly by the continuously increasing environmental requirements. One example of this is the start/stop function, which is already incorporated in many new vehicles for the purpose of saving fuel, in which the engine is automatically switched off when the vehicle is stationary and is automatically restarted in order to drive away. This leads to a higher loading on the starter motor and has to be counteracted by measures such as increasing the conductor cross section and/or increasing the number of brushes, as a result of which, however, the material costs are increased. This leads to efforts to counteract the higher material costs by reducing the assembly costs.